Field of the Invention
The invention relates to an assistance method for adjusting the pressure of a tire fitted to a wheel mounted on a motor vehicle. This adjustment may consist in inflation or deflation.
Description of the Related Art
Increasing numbers of motor vehicles are provided, for safety purposes, with monitoring systems including sensors mounted on each of the wheels of the vehicle, used for measuring parameters such as the pressure or temperature of the tires fitted to these wheels, and intended to inform the driver of any abnormal change in the measured parameter.
These monitoring systems conventionally comprise an electronic module mounted on each wheel, adapted to transmit, to a central unit positioned in the vehicle, signals comprising an identification code of said electronic module and data enabling the pressure of the associated tire to be determined.
In addition to their main function of monitoring the operating parameters of the tires, these monitoring systems also have other functions such as a function of assistance in the adjustment (inflation/deflation) of the pressure of the tires.
At the present time, the assistance method used for the purpose of providing this assistance function usually consists in the following procedures, performed during an action of adjusting the pressure of the tire of a wheel:                transmission, by the electronic module fitted to this wheel, of a sequence of signals, called measurement signals, each comprising data for determining a measured value Pm(t) of the tire pressure,        comparison by the central unit, on the receipt of each measurement signal, of the measured value Pm(t) of the pressure with a predetermined setpoint value Pc,        and then, if the measured value Pm(t) of the pressure corresponds to the value of the setpoint pressure Pc, a procedure of managing the cessation of the pressure adjustment action, comprising a final step of signaling the end of said adjustment action.        
The drawback of this assistance method is that it is necessary to wait for a measurement signal delivered by the electronic module fitted to the wheel in order to update the data required for the assistance function. Consequently, the accuracy of the real value of the pressure obtained is determined by the periodicity of transmission of the measurement signals, and this accuracy may be highly random, notably if the periodicity of transmission of the measurement signals is low (for example, in what is known as the “parking” mode of operation of the electronic modules, for which the periodicity of the measurements reaches a duration of about 15 to 30 seconds), and/or when the type of compressor installed in service stations, having a high free air delivery, is used.